Multilingualism allegedly makes learning new languages easier. However, in view of grammar learning, experimental results so far have been inconclusive. Moreover, multilingualism is often defined as knowledge of more than one natural language, but it is unknown how knowledge of an artificial language such as a programming language fares within this equation. We examined the effect of participants' linguistic and programming experience on their accuracy scores in an artificial grammar learning (AGL) task. Our results revealed no evidence that multilinguals were better in the AGL task than monolinguals. In contrast, participants who reported knowledge of a programming language performed significantly better than non-programmers in this task. I conclude that knowledge of a natural language and that of a programming language have different effects on cognition in view of AGL.